Part 2: An innovative approach to sanitation in Cape Town?

Part 2 [Part 1 may be found here]
In practice, it will probably be a combination of each. The most important thing though is that the function of the system be kept foremost in mind, not the technology. That being said, a quick review of the tech is in order.

Dry toilet systems abound, but are usually dependent on relatively low loading. They are also quite expensive, and don’t work well when used inappropriately (i.e. putting non-biological effluent down them). However, they work very well when combined with a composting system and provide a cyclical approach to nutrients without relying on extensive water use. Perhaps most importantly, once the effluent has been digested by bacteria in the sump, it is sterile and can be used for fertiliser or fuel – potentially even providing a source of income.

Decentralised wet systems (membrane bio reactors for instance) are tech-heavy and require attention, maintenance and energy. However, they are able to treat water to a very high standard so that it can be re-used. In theory, a well-designed packaged plant could fit into a shipping container, be run off a PV array on the roof and connected to an ablution block to deliver sanitation services. Tanked water could be provided occasionally to make up for the losses (typically in sludge drying) but most water would be circulated around the system. It could conceivably be augmented with some level of biogas collection and management of dried sludge for fuel purposes.

Bio-digesters are vessels which generate biogas through the bacterial digestion of organic waste. Industrial scale systems are typically aligned with pig farms, but again the potential exists for small or medium scale systems to be linked with municipal sanitation services. Again, the ‘waste’ becomes a resource for the generation of energy.

Moving on from the technology though, the engagement of end-users is essential, and civil society has an important role to play. Communities in Cape Town have rejected dry-toilet systems as inferior – an understandable viewpoint given the ‘aspirational’ nature of a white, porcelain, flushing loo. But I wonder if there were an income stream from the provision of sewage (as fertilizer to a community garden or as feedstock to a bio-digester operator) whether those perceptions could be shifted.

Based on what I have seen in successful strategies for renewable energy in informal entitlements in India using micro-finance (like Pollinate Energy), I am convinced appropriate solutions for sanitation can be found, with sufficient humility and willingness to engage.

I haven’t done the design work and I’m not a waste-water specialist, but I have been seen a wide range of design processes that challenge the status quo, and the options are always wider than we first imagine.

I believe a first step for Cape Town might be to get some heads around a table – World Design Capital 2014 might be a good forum to do this in. There are bio-tech specialists at UCT (and almost certainly elsewhere), world class engineers and an engaged civil society in the City. Perhaps get a facilitation specialist to manage the process – a team like Meshfield… But put experienced, innovative people around a table, with a brief and a budget and get them thinking, designing and working.

Photo by Sustainable Sanitation (flickr)

Photo by Sustainable Sanitation (flickr)

For what it’s worth, my approach would be:
  • Trial a range of dry-toilet systems aligned to community gardens (Cape Town has poor soil, so nutrients are a limitation); not as a strategy to deliver the services to all, but to showcase how the tech works.
  • Do your best to secure buy-in and support from civic, health and community organisations.
  • Finance some of the investment from your health budget as the payback on ‘prevention’ will always top that on ‘cure’.
  • If it is possible to build a business case around the production of local food, and the stigma (and actual safety and health) of waste-to-food can be managed (which they can), then do so. Frame the venture as a business exercise for value creation from a waste product, and better health and sanitation or a by-product.
Then, commission a packaged plant design with ablution facility, intended to be permanent, that runs a cyclical water re-use system. The system spec should be:
  • energy neutral (i.e. powered by renewables)
  • cycle water
  • provide sterilised, dry sludge that can be used for fuel
This could be a university research project or paid design commission from an innovative engineering firm or start-up. The technology is largely proven and the challenges are cost, durability and scalability. I would suggest a business plan competition at UCT or UWC business schools, with seed finding from the City for the winner for either. The most critical thing is to look at new models for finance, governance and ownership to view the utility as a community asset rather than an entitled service (which can only happen with a business plan and finance strategy).
Finally, get a feasibility study of the critical mass of bio-gas from effluent and value the waste in terms of energy production. If it is viable, let an operator strategize the collection of waste, with a requirement for safe, hygienic and private systems. I know there are no easy solutions to this challenge, if there were, it would be commonplace by now. However, I also know that we have become complacent in our design of municipal infrastructure and that alternative opportunities do exist.
By acknowledging that the status quo (conventional sewers) is impossible in informal settlements, and temporary solutions are not in fact solutions, you create a challenge that must seek new answers.I believe the challenge of innovative delivery of municipal services to informal settlements is one of the chief global challenges of this decade. I also believe it will prove crucial to the future competitiveness of emerging market cities.I would hope there sufficient free thinkers, practical innovators and enlightened governors in Cape Town to at least attempt a fully integrated, multi-level, multi-tech approach to this challenge.

Also read: Pressure Cooker on Steroids Treats Human Waste

This post forms part of a week curating thought, articles, and views on the sanitation situation, in Cape Town, and in the developing world.  The article originally appeared at the blog of Richard Palmer, The Pointy End, on Sunday, 7 July 2013.

There are 3 comments

  1. Paul Kennedy

    This is a really nice review of the challenges. I work in biotech and have been brewing the exact same thoughts over in my head for years. Perhaps it’s time to do something about it.

Comments are closed.